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arXiv 2021年

作者： Muntini, Melania S. Suprayoga, Edi Wella, Sasfan A. Fatimah, Iim Yuwana, Lila Seetawan, Tosawat Cahaya, Adam B. Nugraha, Ahmad R.T. Hasdeo, Eddwi H. Department of Physics Faculty of Science and Data Analytics Institut Teknologi Sepuluh Nopember Surabaya60111 Indonesia Research Center for Quantum Physics National Research and Innovation Agency Tangerang Selatan15314 Indonesia Center of Excellence on Alternative Energy Research and Development Institution Sakon Nakhon Rajabhat University Sakon Nakhon47000 Thailand Program of Physics Faculty of Science and Technology Sakon Nakhon Rajabhat University Sakon Nakhon47000 Thailand Department of Physics Faculty of Mathematics and Natural Sciences Universitas Indonesia Depok16424 Indonesia Department of Physics and Material Science University of Luxembourg L-1511 Luxembourg

Historically, finding two-dimensional (2D) magnets is well known to be a difficult task due to instability against thermal spin fluctuations. Metals are also normally considered poor thermoelectric (TE) materials. Combining intrinsic magnetism in two dimensions with conducting properties, one may expect to get the worst for thermoelectrics. However, we will show this is not always the case. Here, we investigate spin-dependent TE properties of monolayer chromium pnictides (CrX, where X = P, As, Sb, and Bi) using first-principles calculations of electron- and phonon-energy dispersion, along with Boltzmann transport formalism under energy-dependent relaxation time approximation. All the CrX monolayers are dynamically stable and they also exhibit half metallicity with ferromagnetic ordering. Using the spin-valve setup with antiparallel spin configuration, the half metallicity and ferromagnetism in monolayer CrX enable manipulation of spin degrees of freedom to tune the TE figure of merit (ZT). At optimized chemical potential and operating temperature of 500 K, the maximum ZT values (≈ 0.22, 0.12, and 0.09) with the antiparallel spin-valve setup in CrAs, CrSb, and CrBi improve up to almost twice the original values (ZT ≈ 0.12, 0.08, and 0.05) without the spin-valve configuration. Only in CrP, which is the lightest species and less spin-polarized among CrX, the maximum ZT (≈ 0.34) without the spin-valve configuration is larger than that (≈ 0.19) with the spin-valve one. We also find that, at 500 K, all the CrX monolayers possess exceptional TE power factors of about 0.02-0.08 W/m.K2, which could be one of the best values among 2D conductors. © 2021, CC BY.

关键词： Chromium

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Localization transition in three-dimensional stealthy hyperuniform disordered systems

arXiv

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arXiv 2021年

作者： Sgrignuoli, F. Torquato, S. Dal Negro, L. Department of Electrical and Computer Engineering & Photonics Center Boston University 8 Saint Mary’s Street BostonMA02215 United States Department of Chemistry Department of Physics Princeton Institute for the Science and Technology of Materials Program in Applied and Computational Mathematics Princeton University PrincetonNJ08540 United States Division of Material Science and Engineering Boston University 15 Saint Mary’s Street BrooklineMA02446 United States Department of Physics Boston University 590 Commonwealth Avenue BostonMA02215 United States

The purpose of this work is to understand the fundamental connection between structural correlations and light localization in three-dimensional (3D) open scattering systems of finite size. We numerically investigate the transport of vector electromagnetic waves scattered by resonant electric dipoles spatially arranged in 3D space by stealthy hyperuniform disordered point patterns. Three-dimensional stealthy hyperuniform disordered systems (3D-SHDS) are engineered with different structural correlation properties determined by their degree of stealthiness χ. Such fine control of exotic states of amorphous matter enables the systematic design of optical media that interpolate in a tunable fashion between uncorrelated random structures and crystalline materials. By solving the electromagnetic multiple scattering problem using Green’s matrix spectral method, we establish a transport phase diagram that demonstrates a clear delocalization-localization transition beyond a critical scattering density that depends on χ. The transition is characterized by studying the Thouless number and the spectral statistics of the scattering resonances. In particular, by tuning the χ parameter, we demonstrate large spectral gaps and suppressed sub-radiant proximity resonances, facilitating light localization. Moreover, consistently with previous studies, our results show a region of the transport phase diagram where the investigated scattering systems become transparent. Our work provides a systematic description of the transport and localization properties of light in stealthy hyperuniform structures and motivates the engineering of novel photonic systems with enhanced light-matter interactions for applications to both classical and quantum devices. Copyright © 2021, The Authors. All rights reserved.

关键词： Phase diagrams

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Synthesis, Characterization, and performance test of modified Zeolite-Si/Al nanocomposite from pumice and waste cans using slow pyrolysis process for removal pollutant parameters from hard water

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Environmental Nanotechnology, Monitoring and Management 2023年 20卷

作者： Gusti Wibowo, Yudha Sudibyo Rianjanu, Aditya Taher, Tarmizi Susanti, Noni Karo Karo, Pulung Suprihatin Iman Supriyatna, Yayat Prasetyo, Erik Bahfie, Fathan Amin, Muhammad Syarifuddin, Hutwan Safitri, Hana Khairurrijal, Khairurrijal Department of Mining Engineering Institut Teknologi Sumatera Lampung-35365 Indonesia Research Center for Mining Technology National Research and Innovation Agency Lampung Indonesia Department of Material Engineering Institut Teknologi Sumatera Lampung-35365 Indonesia Department of Environmental Engineering Institut Teknologi Sumatera Lampung-35365 Indonesia Physics Department Universitas Lampung Lampung Indonesia Department of Environmental Science Postgraduate Program Universitas Jambi Jambi 36122 Indonesia Laboratory of Mine Environmental Department of Mining Engineering Institut Teknologi Sumatera Lampung-35365 Indonesia Department of Physics Institut Teknologi Sumatera Lampung-36365 Indonesia Department of Physics Institut Teknologi Bandung Bandung 40132 Indonesia Center for Green and Sustainable Materials Institut Teknologi Sumatera Indonesia

Hard water is one of crucial problems in the world due to its pollutant parameters. Adsorption is a promising method for treating hard water because of its benefits such as low-cost, easy to use, acceptable, and easy to maintenance. In this study, we utilized zeolite functionalized with silicon/aluminum (Ze-Si/Al) as adsorbent materials for hard water treatment. Ten different ratios of Si/Al were added into zeolite by modifying the solid waste source concentration (pumice and cans). The optimum sample was then further tested with different parameters including contact time, dye concentration, and isotherm models. The zeolite-Si/Al adsorbent was characterized by Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), and X-Ray Fluorescence (XRF). Results of this study have showed that the best functionalized zeolite was that with Si/Al ratio 0.67, which has higher sorption ability. In contact time test, the equilibrium was reached after 300 min. This study also informed that the concentration of dyes will give impact on removal of pollutant parameters. Isotherm model of Ze-Si/Al fitted with Langmuir method. This study also discussed the potential development and future research direction. Thus, this study is a crucial report to develop the information about waste utilization as source of Si/Al to increasing quality of zeolite. © 2023 Elsevier B.V.

关键词： Adsorption Hard water Wastewater Wastewater treatment zeolite-Si/Al

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Coconut waste to green nanomaterial: Large scale synthesis of N-doped graphene nano sheets

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Nano-Structures and Nano-Objects 2023年 36卷

作者： Siburian, Rikson Tang, Liang Wei Alias, Yatimah Tok, Alfred Iing Yoong Goei, Ronn Simanjuntak, Crystina Tarigan, Kerista Paiman, Suriati Goh, Boon Tong Anshori, Isa Kurniawan, Cepi Postgraduate Program Department of Chemistry Faculty of Mathematics and Natural Sciences Universitas Sumatera Utara Medan 20155 Indonesia Department of Chemistry Faculty of Mathematics and Natural Sciences Universitas Sumatera Utara Medan 20155 Indonesia Carbon and Frankincense Research Center Universitas Sumatera Utara Medan 20155 Indonesia Department of Chemistry Faculty of Science Universiti Malaya Kuala Lumpur 50603 Malaysia University Malaya Centre for Ionic Liquids (UMCiL) Universiti Malaya Kuala Lumpur 50603 Malaysia School of Materials Science and Engineering Nanyang Technological University 50 Nanyang Avenue Singapore 639798 Singapore Department of Physics Faculty of Mathematics and Natural Sciences Universitas Sumatera Utara Medan 20155 Indonesia Physics Department Faculty of Science Universiti Putra Malaysia Selangor (Serdang) Seri Kembangan 43400 Malaysia Low Dimensional Materials Research Centre Department of Physics Faculty of Science University of Malaya Kuala Lumpur 50603 Malaysia Biomedical Engineering Department School of Electrical Engineering and Informatics Bandung Institute of Technology Bandung 40132 Indonesia Research Center of Nanoscience and Nanotechnology Bandung Institute of Technology Bandung 40132 Indonesia Chemistry Department Faculty of Mathematics and Natural Sciences Universitas Negeri Semarang Semarang 50229 Indonesia Functional Material Research Center Universitas Negeri Semarang Semarang 50229 Indonesia

In this paper, a breakthrough was achieved in large-scale production of N-doped Graphene Nano Sheets (N-GNS) using coconut fruits. The main objectives were to produce N-GNS on a large scale and assess its electrical conductivity. The process involved two key steps: first, producing GNS from coconut fruits through pyrolysis, and then generating N-GNS by doping with nitrogen using ammonia solution at room temperature. Various analytical techniques were used to characterize the produced N-GNS, including X-ray Diffraction (XRD), Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM-EDS), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), Raman spectroscopy, and electrochemical cyclic voltammetry and electrochemical impedance spectroscopy. The XRD data indicated that the C (002) peak of N-GNS shifted to a higher 2θ value (2θ = 24.72°) compared to GNS (2θ = 23.86°), suggesting an incorporation of nitrogen into carbon structure in N-GNS. This was further supported by XPS data, which identified N-pyridine (BE = 402.0 eV) and C-N (BE = 286.8 eV) in N-GNS. TEM images showed that N-GNS had a flat surface, and the distance between graphene layers slightly expanded (0.36 nm) compared to graphene layers (0.34 nm). SEM images and EDX data validated the morphology, resembling honeycomb lattices, with a significant content of N atoms. Raman data successfully identified the D-band and G-band in N-GNS, further validating its production. Most importantly, N-GNS exhibited electrical conductivity, making it a promising candidate for conductive and supporting materials in various applications. The significance of this research extends beyond N-GNS production, opening up new avenues for the sustainable synthesis of valuable nanomaterials from coconut fruit waste, contributing to both graphene technology and environmental conservation. © 2023 Elsevier B.V.

关键词： C-sp2 Electrical conductivity Graphene nano sheets N-graphene nano sheets N-pyridine XPS

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Deceleration performance and stopping distance of hybrid composite brake lining pads of basalt and clam shell

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AIP Conference Proceedings 2023年第1期2568卷

作者： I. Ketut Adi Atmika I. Gusti Agung Kade Suriadi I. Nyoman Sutantra I. Dewa Gede Ary Subagia 1)Mechanical Engineering Department of Udayana University Street of Bukit Jimbaran Bali 80361 Indonesia 3)Technology and Material Research Center of Udayana University Street of Bukit Jimbaran Bali 80361 Indonesia 4)Doctoral Program of Engineering Science Engineering Faculty of Udayana University Street of PB Sudirman Bali 80114 Indonesia 2)Mechanical Engineering Department of Institut of Sepuluh Nopember Surabaya 60111 Indonesia

Brake lining is one of the components of the braking system on a vehicle that plays an important role for the safety of the driver. Recently, the development of brake lining materials has attracted the attention of many researchers. At first many brake pads were made of asbestos as the main material, but this brake lining material has begun to be abandoned because it has a negative impact on health and the environment. This paper presents the results of research on the development of a hybrid composite as a brake lining material. This hybrid composite is composed of the main ingredients of basalt and green clam shell waste, as well as a small amount of alumina with phenolic resin as a binder. Hybrid composite brake lining material is made through a sintering process with an emphasis of 2 tons for 30 minutes at a constant temperature of 150°C. Hybrid composite brake pads made 3 variations of weight fraction were tested on a motorcycle to see the performance of deceleration and braking distance. Also tested brake lining with asbestos material as a comparison. The lowest deceleration performance was asbestos brake lining at 6.79 m/s2, while the highest deceleration was HC4 brake lining (35% basalt-15% clam shell) of 11.51 m/s2. While the shortest braking distance is HC4 brake pads (35% basalt-15% shell) of 3.02 meters, while the longest braking distance of asbestos is 15.18 meters. The increase in the percentage of basalt content and the decrease in the percentage of clam shell content indicate a tendency to increase the magnitude of deceleration, and a tendency to decrease the braking distance for each vehicle's initial speed.

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Managing laundry wastewater 1

Managing laundry wastewater

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1st International Conference on Smart City Innovation, ICSCI 2018

作者： Watiniasih, N.L. Purnama, I.G.H. Padmanabha, G. Merdana, I.M. Antara, I.N.G. Study Program of Biological Sciences Faculty of Mathematics and Natural Sciences Udayana University Indonesia Laboratory of Integrated Material Engineering and Environmental Technology Udayana University Indonesia Study Program of Public Health Faculty of Medicine Udayana University Indonesia Faculty of Veterinary Science Udayana University Indonesia Mechanical Engineering Study Program Faculty of Engineering Udayana University Jl. Raya Kampus UNUD Kampus Bukit Jimbaran Bali Jimbaran80361 Indonesia

Laundry services are emerging in every corner of Bali, particularly at suburban area, from cities to villages. These services help the community to ease their burden. However, the burden for the environment is increase. The wastewater from the laundries should be controlled, which should be handled natural ways. One way of reducing the dangerous chemical from the laundry wastewater can be done by Vertical-Sub-surface Flow Constructed Wetland system, using volcanic rocks as substrate of plant grow and the plant as filters. This study aimed to investigate the effectiveness of volcanic rock and Canna plants as a filter for the laundry wastewater. The volcanic rock as substrate for the plant grows was place in layers in a drum and the laundry wastewater was flowed. The parameter of wastewater laundry, such as TDS, BOD, COD and total phosphate were measured before and after treatment. The treatment was run for 6 weeks. The result shows that this system is effective that overall can reduce the parameter measured for 53.86%. © 2019 IOP Publishing Ltd. All rights reserved.

关键词： Volcanic rocks

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Measurement and analysis of thermal conductivity of ceramic particle beds for solar thermal energy storage

arXiv

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arXiv 2021年

作者： Chung, Ka Man Zeng, Jian Adapa, Sarath Reddy Feng, Tianshi Bagepalli, Malavika V. Loutzenhiser, Peter G. Albrecht, Kevin J. Ho, Clifford K. Chen, Renkun Material Science and Engineering Program University of California San Diego San DiegoCA92093 United States Department of Mechanical and Aerospace Engineering University of California San Diego San DiegoCA92093 United States George W. Woodruff School of Mechanical Engineering Georgia Institute of Technology AtlantaGA30332-0405 United States Concentrating Solar Technologies Department Sandia National Laboratories 1515 Eubank Blvd. SE AlbuquerqueNM87123 United States

A systematic study was performed to measure the effective thermal conductivity of ceramic particle beds, a promising heat transfer and thermal energy storage media for concentrating solar power (CSP). The thermal conductivity of the ceramic particle beds was measured using a transient hot-wire (THW) method within a temperature range of room temperature to 700 oC, the target operating temperature of the next-generation CSP systems. Two different types of ceramic particles were examined: (1) CARBOBEAD HSP 40/70 and (2) CARBOBEAD CP 40/100 with the average particle sizes of ~ 400 μm and ~280 μm, respectively, and thermal conductivities ranging from ~0.25 W m-1 K-1 to ~0.50 W m-1 K-1 from 20 oC to 700 oC in both air and N2 gas. The gaseous pressure dependence of the thermal conductivity of the ceramic particle beds was also studied in the N2 environment to differentiate the contributions from gas conduction, solid conduction, and radiation. Calculations using the Zehner, Bauer, and Schlünder (ZBS) model showed good agreements with the measurements. Based on the model, it is concluded that the effective thermal conductivity of the packed particle beds is dominated by the gas conduction while the solid conduction and radiation contributes to about 20% of the effective thermal conductivity at high temperature. Copyright © 2021, The Authors. All rights reserved.

关键词： Heat storage

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Ultrafast Formation of Charge Transfer Trions at Molecular-Functionalized 2D MoS2Interfaces

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Angewandte Chemie 2024年第30期136卷

作者： Yuancheng Jing Kangkai Liang Nicole S. Muir Hao Zhou Zhehao Li Joseph M. Palasz Jonathan Sorbie Chenglai Wang Scott K Cushing Clifford P. Kubiak Zdeněk Sofer Shaowei Li Wei Xiong Department of Chemistry and Biochemistry University of California San Diego 9500 Gilman Drive MC 0358 La Jolla California 92093-0358 United States Material Science and Engineering Program University of California San Diego 9500 Gilman Drive MC 0418 La Jolla California 92093-0418 United States Division of Chemistry and Chemical Engineering California Institute of Technology 1200 E California Blvd MC 127–72 Pasadena California 91125 United States Department of Inorganic Chemistry University of Chemistry and Technology Prague Technická 5 166 28 Prague 6 Czech Republic

In this work, we investigate trion dynamics occurring at the heterojunction between organometallic molecules and a monolayer transition metal dichalcogenide (TMD) with transient electronic sum frequency generation (tr-ESFG) spectroscopy. By pumping at 2.4 eV with laser pulses, we have observed an ultrafast hole transfer, succeeded by the emergence of charge-transfer trions. This observation is facilitated by the cancellation of ground state bleach and stimulated emission signals due to their opposite phases, making tr-ESFG especially sensitive to the trion formation dynamics. The presence of charge-transfer trion at molecular functionalized TMD monolayers suggests the potential for engineering the local electronic structures and dynamics of specific locations on TMDs and offers a potential for transferring unique electronic attributes of TMD to the molecular layers.

关键词： charge transfer trion Time-resolved interfacial-sensitive spectroscopy sum frequency generation molecular- functionalized monolayer TMD

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Comparative analysis of the efficiency of gas grafting reaction of different types of Hanji with palmitoyl chloride

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Palpu Chongi Gisul/Journal of Korea Technical Association of the Pulp and Paper Industry 2019年第3期51卷 90-97页

作者： Choi, Kyoung-Hwa Lee, Kwang Seob Lee, Jae-Hoon Lee, Myoung-Ku Ryu, Jeong-Yong Changgarig Institute of Paper Science and Technology Kangwon National University Chunchon24341 Korea Republic of Program of Paper Science and Engineering Division of Forest Material Science and Engineering College of Forest and Environmental Sciences Kangwon National University Chuncheon24341 Korea Republic of

This study was conducted to investigate the changes in the grafting efficiency of different types of Hanji, such as a raw materials and manufacturing methods varying different palmitoyl chloride concentrations and reaction temperatures. The results showed that the raw material of Hanji affected the grafting efficiency. The grafting efficiency of Hanji produced using the bast fiber of Edgeworthia chrysantha Lindl. was particularly excellent. Meanwhile, the amidation between anionic polyacrylamide (A-PAM) and palmitoyl chloride was speculated to occur in the case of Hanji at which A-PAM was added. However, the manufacturing process of Hanji had little influence on the graft reaction efficiency. The strength and brightness of all Hanji samples decreased via the gas grafting treatment, regardless of the kind of Hanji. The changes in the hydrophobicity, physical and optical properties of Hanji samples via gas grafting increased with the increasing palmitoyl chloride concentration and reaction temperature. © 2019 Korean Technical Assoc. of the Pulp and Paper Industry. All rights reserved.

关键词： Grafting (chemical)

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Artificial aging characteristics of hydrophobic hanjis grafted by gaseous palmitoyl chloride

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Palpu Chongi Gisul/Journal of Korea Technical Association of the Pulp and Paper Industry 2019年第3期51卷 98-107页

作者： Choi, Kyoung-Hwa Lee, Kwang Seob Lee, Jae-Hoon Lee, Myoung-Ku Ryu, Jeong-Yong Changgang Institute of Paper Science and Technology Kangwon National University Chunchon24341 Korea Republic of Program of Paper Science and Engineering Division of Forest Material Science and Engineering College of Forest and Environmental Sciences Kangwon National University Chuncheon24341 Korea Republic of

This study was conducted to investigate the effects of gas grafting treatment on the durability of Korean traditional paper i.e., Hanji. Dry heating- and humid heating-accelerated aging tests were performed. Further, the properties of each Hanji sample, including strength, optical property, Cobb size degree, and static contact angle, were analyzed. The decrease in the strength and optical characteristics of the Hanji hydrophobized via gas grafting with palmitoyl chloride during artificial aging was found to be more significant than that of untreated paper. The decrease in durability was speculated to be caused by the residual free fatty acids in the Hanji. In contrast, no changes in the Cobb size and static contact angle of the hydrophobic Hanji occurred during accelerated aging. In summary, the hydrophobicity of Hanji grafted with palmitoyl chloride remained unchanged during 30 days of dry-heating aging and 60 days of humid-heating aging, however, the durability of paper material, including strength and optical properties, deteriorated. Therefore, the attenuation and elimination of residual free fatty acids must be investigated to prevent the decrease of durability. © 2019 Korean Technical Assoc. of the Pulp and Paper Industry. All rights reserved.

关键词： Grafting (chemical)

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